The Privacy Commissioner is closely monitoring Facebook developments after the social network said it was considering running users' profile photos through its controversial facial recognition technology.

Facebook revealed its plans in an update to its data use policy on the site on Thursday that is intended to improve the performance of its "Tag Suggest" feature.

Facebook already uses technology that automatically identifies faces in newly uploaded photos by comparing them only to previous snapshots in which users were tagged. But soon the social network could use your profile picture to suggest tags.

The site's chief privacy officer, Erin Egan, told Reuters that adding members' public profile photos would give users better control over their personal information, by making it easier to identify posted photos in which they appear.

"Our goal is to facilitate tagging so that people know when there are photos of them on our service."

Users uncomfortable with facial recognition technology would be able to opt out of the feature so their public profile photo would not be included in the facial recognition database.

Egan said Facebook was not using facial recognition technology for any other features, but that could change.

"Can I say that we will never use facial recognition technology for any other purposes? Absolutely not."

But she said if they decided to use it in different ways, they would "continue to provide people transparency" about that and control.

Facial recognition technology has been a sensitive issue for technology companies, raising concerns among some privacy advocates and government officials.

Tag Suggest, which the company introduced in 2011, is not available in Europe because of concerns raised by regulators there, Reuters reported.

Google's social network, Google+, also employs similar technology, but requires users to opt in.

A spokesman for New Zealand Privacy Commissioner Marie Shroff said her office was watching the developments closely, but it would be some time before the technology was rolled out. It was not mandatory and users could opt out, he said.

Facebook was aware of people's privacy concerns and would not implement anything that would drive users away or make them rebel.

"It's one of these developing technologies that we're monitoring closely and we're keeping an eye on the privacy implications. It's something that they're floating as an idea and we noted it with interest," said the privacy spokesman.

Also in its update announcement on Thursday, Facebook amended its Statement of Rights and Responsibilities so that members under 18 years of age were deemed to have affirmed that a parent or legal guardian agreed to allow marketers to use some of their personal information in ads.